Sylvia Burwell testifies before a U.S. Senate Health, Education, Labor and Pensions Committee confirmation hearing on her nomination to be secretary of the Health and Human Services Department, on Capitol Hill in Washington May 8, 2014. (REUTERS/Jonathan Ernst)

A federal court upheld Obamacare’s individual mandate tax Tuesday, but the plaintiff in the lawsuit alleging Congress passed the tax unconstitutionally have vowed to bring the case to the Supreme Court.

Matt Sissel, a self-employed artist and National Guard serviceman from Iowa, sued the Department of Health and Human Services for subjecting him to the individual mandate tax because he chooses not to purchase health insurance.

Sissel “does not have, need, or want health insurance,” he wrote in his original lawsuit, and “is able to and does pay for any and all of his medical expenses out of pocket,” but is still subject to the individual mandate tax.

Timothy Sandefur, Sissel’s representation and a principal attorney at the Pacific Legal Foundation, argued before the court that because the Supreme Court ruled in 2012 that the individual mandate penalty is a tax, it’s unconstitutional because Obamacare didn’t originate in the House of Representatives, as all tax bills are required to by law.

But a three-judge panel on the U.S. Court of Appeals for the D.C. Circuit ruled Tuesday that although the Supreme Court has labeled the individual mandate as a tax, Obamacare as a whole is not intended to be a “bill for raising revenue” and the individual mandate tax is merely “incidental” to the health-care law’s goal of increasing health insurance coverage.

“The decision today is disappointing, but not very surprising,” Sandefur wrote in a statement. “We expected that either side in this case would appeal, and eventually this case will likely have to go before the Supreme Court.”

“The D.C. Circuit for the first time holds that judges can decide for themselves what the ‘main object or aim’ of a tax is, and then pick and choose whether constitutional rules on the enactment of new taxation should apply,” Sandefur writes. “We think that’s wrong, and that’s what we’ll be taking to the Supreme Court if necessary.”